Well, long troubelshooting road. No thanks to Aerotronics and their "plug and play panel" Steinair next time. Cost me 6-8 hours and alot of frustration.
3 problems.....Aero. ran 2 separate 2 conductor sheild wires from the EFIS to molex at cockpit...white and blue white each....no markings. Jeez. Said they don't stock 4 conductor sheilded...but aft cable was 4 conductor. Figured that was the likely spot for the problem. The DB 25 at the EFIS is really hard to get to so I am avoiding going that route.
Seemed like I had a 50-50 chance with 2 pairs of similar yet unmarked wires so decided to reverse the wires at the molex.. 1-2 for 4-5. Couldn't get pins out of the aft end of the molex so cut off and re-pinned the molex. Still no joy.
Then began metering out the wires from the fwd end of the molex to the 9 pin Dsub at magnetometer. Found wh-gr and wh-or wires reversed in dsub...from Aerotronics. Could not get pins out of Dsub, so reversed them at molex.
But, still had to reverse the two blue-white pairs back as they were right to begin with by pure luck.
